Archive for the ‘Fitzinger’s Rain Frog’ Tag

After four months of continual sun and no rain the weather briefly changed. Over the course of the last week the clouds had been gathering, a portent of what was about to happen. There were several nights with a brief light drizzle, not enough to dampen the ground but just enough to wash the layer of dirt covering the plant leaves. Then one night the sky grew dark and a heavy shower dropped enough water to soften the hard, dry ground. Finally, one afternoon a really heavy deluge poured out of the heavens, two and a half inches is as many hours. Immediately the Fitzinger’s Rain Frogs, (Craugastor fitzingeri), started calling. This was to herald a sudden coming to life of several amphibian species.

Fitzinger’s Rain Frog, (Craugastor fitzingeri)

Over the next few hours the calls of the Milky Frog, (Trachycephalus venulosus), began increasing in number and intensity. The sun was setting, the daily environmental trigger that stimulates the frogs into emerging from their daytime hiding places, but over the dry season only one or two individuals of few species. Now, however, a greater number of participants was joining the choral gathering.

Milky Frog, (Trachycephalus venulosus)

The Banana Frogs, (Dendropsophus ebreccatus), which for the past four months had been restricted to a solo, forlorn crooner was now accompanied by many more to form a backing group. The loud nasally calls of the Masked Smiliscas, (Smilisca phaeota), entered to swell the ever-increasing cacophony. All semblance of rhythm, cadence and orchestration disappeared as more and more frogs entered into what was becoming a free for all, each male trying to drown out his neighbor. Up in the tree tops the Red-eyed Green Tree Frogs, (Agalychnis callydryas), were chirping from all quarters. Down on the ground boomed the loud whooping of Savage’s Thin-fingered Frogs, (Leptodactylus savagei). The sound of a mini jackhammer that is the mating call of the Marine Toad, (Chaunus marinus) along with the chucking calls of the rain frogs completed the din.

As the evening progressed, it was however, the calls of the Milky Frogs that became so intense that they could be heard from some distance away. The ruckus continued well into the night. The next morning the surface of the pond was covered in a gelatinous film containing the eggs of the milky frogs. These are some of the fastest developing amphibian eggs I have ever encountered. Within 24 hours the tadpoles have hatched and entered the water where they can be observed as wriggling black swarms just beneath the surface. After several weeks they will be seen everywhere as tiny, newly emerged froglets sitting on the vegetation surrounding the pond.

Sadly for the amphibians, that one wet night was all they got. The next day it was back to normal dry season conditions. It won’t be long before the rains truly arrive though. One other creature to be seen around the pond at night, sleeping on top of the vegetation are the juvenile Green Iguanas, (Iguana iguana), newly hatched. Their comatose, lime-green bodies can be found at the ends of the long branches but a lingering flashlight beam will soon stir them into a state of semi-consciousness ready to jump off and run away at the slightest disturbance. If you are lucky you will also catch sight of the newly emerged Common Basilisks, (Basiliscus basiliscus). They are harder to see as they sleep vertically and are more muted in coloration. The hind legs sticking out sideways from the stems where they sleep is quite often a giveaway as to their presence.

Green Iguana, (Iguana iguana)

Philip Davison Is a Biologist, Writer and Photographer Based in Costa Rica

I made an earlier than normal return to Bosque this year. The wet season had seen its share of rain but now the heavy showers are interspersed with long periods of blue sky and bright sun. Mammal, bird, reptile, amphibian and butterfly sightings are good.

I keep a daily nature diary of animals and plants, (flowering and fruiting), that I have seen at the lodge. At the end of the week the lists are added to the bottom of this blog which allows people to see what is going on in advance of their visit to Bosque or to keep in touch when they have left. Anyone reading but not visiting can gauge the amount of activity taking place in the natural world down on the tip of the Osa Peninsula, Costa Rica.

This year I have decided to add something extra, something a little different. Birders have their “Big Year” so I thought it might be nice to have a big year but not limiting myself to the avifauna, but rather everything. It won’t take much more effort over and above what I already record and catalogue. It is not competitive either, just a bit of fun. It will enable me to post a weekly update of cumulative numbers across the board of species inventories. The readers will then be able to see at a glance the amount of fauna and flora that can be experienced and over what period of time at Bosque.

The records will be confined to the 800 acres that constitute the grounds of Bosque del Cabo and will be based on casual observations. Hopefully I should get some photos to post too.

Doing the Rounds

Around the grounds there are the usual mammal sightings with Agoutis, (Dasyprocta punctata), White-nosed Coatis, (Nasua narica), and Red-tailed Squirrels, (Sciurus granatensis), in the gardened areas in front of the restaurant. Spider Monkeys, (Ateles geoffroyi), Howler Monkeys, (Allouata palliata), and White-faced Monkeys, (Cebus capucinus), can be seen just about everywhere around the grounds. The White-faced Monkeys have been up to their usual nasty tricks. One couple out in the garden was trying to photograph a Chestnut-mandibled Toucan, (Ramphastos swainsoni), when a White-faced Monkey grabbed and dispatched the unfortunate bird. It wasn’t the photograph they were looking for but it makes for a talking point back home.

One night, just before dinner, a Kinkajou, (Poto flavus), came into the bar, which was full of guests at the time, and made its way up one of the support poles into the roof and disappeared from view. Kinkajous are not uncommon around the grounds of Bosque and can quite often be heard up in the tree tops at night but this was the first sighting in the bar.

Summer Calling

The Scarlet Macaws can be seen in the morning flying east to the Golfo Dulce beaches where they take up their daily occupancy of the almond trees, the nuts forming a staple part of their diet. Later in the afternoon they can be flying this time west returning to roost for the evening. Their strict adherence to a timetable allows guests to position their cameras to frame the sea and the sky then just wait for the macaws to fly by and fill the foreground space between.

I thought I might make it back before the migrant birds returned but they got here before me. The very distinctive call of the Summer Tanger, (Pingara rubra) can be heard from the vegetation all around the lodge and will continue to be so for the next few months. The Dusky-capped Flycatcher, (Myriarchus tubiculifer), is another bird with a soft yet unmistakable call which is being heard all around the restaurant area and mango orchard at the minute.

Prior to their visit, bird calls are something that a visitor to the tropics should acquaint themselves with as not only will they allow you to hear what is around, but also where it is which is essential if you want to spot them. Looking for birds within the depth of the forest is a somewhat difficult task due to the obstructive presence of so much vegetation. The open areas, gardens and forest edges are your best bet for seeing much of the bird life.

At the moment within the darker confines of the forest beneath the canopy the Red-capped Manakin, (Pipra mentalis), and the Blue-crowned Manakin, (Pipra coronata), are calling as well as the Rufus Piha the call of which sounds like someone giving a wolf whistle.

In front of the restaurant the Roadside Hawk ,(Buteo magnirostris), Crested Caracaras, (Caracara cheriway), and Yellow-headed Caracaras, (Milvago chimachima), are a daily sight along with the ever present Black Vultures and Turkey Vultures.

Spotted Frogs

Despite the fact that it is still wet, the Tink Frogs, (Diasporus diastema), have now all but stopped calling. Down by the pond the Red-eyed Green Tree Frogs, (Agalychnis callidryas), are still present along with the Marine Toads, (Rhinella marinus) and Savage’s Thin-fingered Frog, (Leptodactylus savegei). There are one or two Banana Frogs, (Dendropsophus ebrecattus), sitting on the Water Hyacinths, (Eichhornia crassipes), and the occasional call of a Parachuting Red-eyed Green Tree Frog, (Agalychnis spurelli), can be heard. The Gladiator Frogs, (Hypsoboas rosenbergi), that were out in profusion a few months ago have disappeared. There have been one or two Masked Smiliscas, (Smilisca phaeota), calling too and as the sun sets you can hear the distinctive “Chuck” of Fitzinger’s Rain Frog, (Craugastor fitzingeri).

The Red-eyed Green Tree Frogs are still spawning and their eggs can be found in distinctive gelatinous clusters hanging beneath the leaves overhanging the pond which make an easily available food source for the Cat-eyed Snakes, (Leptodeira septentrionalis). Once the sun sets out come the snakes. They make their way over the surface of the pond and over the vegetation behind, tongues flicking in and out in search of that protein packed jelly. One night I found a Terciopelo sitting above head height on a leaf behind the pond. The occasional sleeping Basilisk, (Basaliscus basaliscus), may also be encountered but they are easily disturbed. You make get a shot but it doesn’t take much to cause them to fall to the ground and run for cover. While out at night you cannot fail to see, especially if looking for eyeshine, the tell tale diamond sparkle coming from the eyes of Wandering Spiders, (Cupiennius sp) sitting on top of the leaves. One night I had fun taking some pictures of a tiny katydid down by the Bosque pond. I have no idea what species it is but it was quite photogenic.

Only When The Sun Shines

As the weather is reasonably dry and bright, at least on some days, the butterflies take to the wing. There are neither a huge number of species nor many individuals of each species to be seen this time of year. If you do go for a walk on a sunny day you should get to see some of the more brightly colored species around the grounds, particularly at the Lantana bush where several species of Longwings will be flitting from flower to flower in search of nectar. The earlier you go the better it is to get the photographs before they are fully warmed up and less likely to settle for any great period of time.

The same applies to the pond and the dragonflies. There are very few species around at the moment. But if you watch them, observing where they land, then you can set up your camera and wait. With a little patience you should get a fairly good chance of a close-up shot.

Fruitless Search

The end of the wet season is not the best time to find either flowers or fruit. The rain will have ensured that the forests have a deep verdant green aspect to them. But as we move into that transitional period from wet to dry, many of the plants are stimulated into bearing flowers. By the time we get into December and January there will be a greater, sometimes subtle and at other times garish, display of color throughout the forest. For now though you just have to enjoy the deep greens. If you thought green was green you were very much mistaken. Find a vantage point and look out over the forest. You will see emerald, jade, olives, lime, bottle green, sea greens, pea green in fact green in every shade and hue you could imagine.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

One of the most compelling sites of the rainforest is ubiquitous presence of the industrious Leaf-cutter Ants, (Atta sp) which seemingly never rest. When they are not active their trails can be seen as clear cut paths that run through lawns and across the forest floor. When they are active, the trails resemble rivers of green moving leaf fragments, which the majority of the workers heading back towards the nest are carrying in their mandibles above their bodies.

Once the leaf is taken into the nest it is dropped and then the work of another caste begins. It chops the leaf into smaller fragments. Descending down into the depths of the nest the workers get smaller and smaller progressively cutting the leaf into ever finer fragments which by the time they reach the nest gardens are processed into a grey chewed up mulch. The ants defecate on this which adds amino acids and enzymes. This is now the compost on which they grow a very specific fungus that ultimately provides food and sustenance for all the ants in the colony, (upto 8 million of which exist in a mature colony).

This last week there has been a tremendous amount of leaf-cutter activity on all of the Bosque trails and also by my cabin. Here was a perfect opportunity to try and get some pictures. This is never an easy task. You have to get the camera in a position where you can see the ants passing through a plane of view. Due to the close proximity of the lens to the subject when an ant does pass by it does so very quickly so the shutter speed has to be high. The distance from the lens means you have a shallow field of view, so to increase your chances of getting one or two in the right plane; you have to close the aperture right down. A fast shutter speed and a minute aperture allow very little natural light to enter so you have to provide a lot of light by way of flash. I use 5 separate flash units. Even then, the chances of getting one at the right exposure filing the frame are slim, most of the ants are entering or exiting the frame or are too far away or are too close. But due to the number of them all moving in the same direction, then you should get one or two keepers, it depends on how much time and patience you have.

It has been a mixed bag with the weather this week. There have been showers, sun and cloud cover. This week has also seen the first violent thunderstorm of the season. In the small hours of Thursday morning, for two hours the sky was lit and the buildings were shaken by the thunder and lightning directly overhead. This was accompanied by an inch and a half of rain. But as dawn broke and the sun rose, so did the clouds eventually disappear and it turned out to be a beautiful day.

Amazing Finds

We had a couple staying this week that were evaluating the potential of Bosque del Cabo as a suitable location for clients booking holidays through their travel agency. Their clients are more nature oriented, which fits the profile of most of Bosque’s visitors; people come because of Bosque’s reputation as one of the best and most biodiverse rain forest lodges in Costa Rica.

Having completed the hotel inspection, it was time to hit the trails. It wasn’t long before their eyes were opened as to why Bosque has achieved its renowned status. Once again, as so many visitors before them, they were walking the Titi Trail watching an abundance of monkey activity, when from down the trail came walking towards them a Puma, (Puma concolor). The cat came closer and closer, it then stopped, looked at them, turned and walked off into the forest. From the description, “It had a short tail”, it was almost certainly the resident female Puma “Half tail”.

The excitement was not over for the day though. After relating the tale of their amazing experience over dinner, they returned to their cabin only to be attracted to something making a noise in the tree outside. They went out onto the deck and there was a Northern Tamandua, (Tamandua mexicana), using its powerful front legs and long sharp claws to rip into the bark of a tree in order to access and feed on the termites inside. They didn’t manage to get a picture of the cat but they did get a good photograph of the anteater.

Odd Sighting

The Titi Trail seems to be an endless source of great wildlife sightings. Not long after the Puma episode, one of the Bosque staff was working on the trail when he had waddling down the path towards him a large animal about the size of Shetland Pony, with small ears and a long snout. This description fits only creature, Baird’s Tapir, (Tapiris bairdii). I have been walking the trails of Bosque for 12 years and have occasionally come across tapir tracks, even as close as my cabin, but I have never seen a tapir in the flesh on the grounds.

Tapirs are odd-toed animals related to horses and rhinoceroses; they all belong to the mammalian order Perissodactyla. Baird’s Tapir is the only odd-toed mammal native to Central American. They are browsers, feeding on low lying vegetation and fruit. Water is essential to the life of the tapir, they like pools in which they can wallow. Bosque is at the top of a hill and there is no lying water so this individual was probably a transient on its way somewhere else.

Mango Surprise

The mango trees are now hanging with fruit which is starting to ripen. This is attracting the attention of many fruit eating animals or those that would just take the opportunity of partaking of the frugivorous feast. One night while I was walking near the mango orchard I could hear a lot of movement coming from the uppermost branches. As I stood watching, a creature fell to the ground with a bump along with several of the mangoes. Initially all I could see was the bright orange eye-shine reflecting back from my flashlight beam. The fall did not seem to have caused it any trauma as it progressed to climbing back into the tree.

By the time it made its way up in the branches again I could see what it was, a Kinkajou, (Poto flavus). This one was not alone; several more made their presence know, not by coming into view, but by the distinctive nasal snort followed by short high pitched whistles. There must have been 3 or 4 above my head which may have been a family all gorging themselves on the abundance of succulent mango flesh surrounding them.

Raining Frogs

It might come as no surprise but when the rains arrive it stimulates the rain frogs into calling. The rain frogs can be heard throughout the year but with increasing wet conditions, more species and more individuals are induced to call. This time of year, all night long you will hear the Tink Frogs, (Diasporus diastema), with the distinctive metallic “tink” song. As the sun sets, you will quite often be aware of soft “chuck, chuck, chuck, chuck” sounds coming from a variety of locations. These are male Fitzinger’s Rain Frogs, (Craugastor fitzingeri), both calling for a mate and telling other males to stay away. Unfortunately, the calls also alert those night time predators on frogs, the Fringe-lipped Bats, (Trachops cirrhosus). The calls usually echo back and forth with a regular time interval which makes it difficult for the bat to isolate where the call is coming from.

Fitzinger’s Rain Frog is not a very large amphibian but despite its size is quite robust. It has a mottled fawn and brown skin with small black spots and covered in small raised warts. As with many frogs they are mostly nocturnal. The rain frogs also don’t need to return to the water to reproduce. They pair up and then deposit 10-30 large, yolk-filled eggs in the leaf litter on the forest floor. The larvae develop within the egg, (there is no free-swimming tadpole stage), until about 8 weeks and then emerge as fully formed but tiny copies of the adults.

This individual I inadvertently disturbed early in the morning. I took advantage of the good lighting and the fact that he didn’t seem too keen to hop away, or at least not till I had taken some good profile shots of him.

Philip is a biologist, writer and photographer as well as the onsite naturalist guide at Bosque del Cabo Rainforest lodge on the Osa Peninsula, Costa Rica.

Sadly, as far as I am concerned, with the rainy season the butterfly numbers are past their peak. There are still enough around but the figures are on the downturn. One morning, the sun was shining and didn’t have a tour, so I decided to head out with the camera and see what may be around. I wasn’t looking for anything in particular just whatever happened to be there. At one point I came across at longwing passionflower butterfly, (Heliconius cydno), flitting from flower to flower searching for and feeding on the nectar that provides the butterfly with energy for flight. I also noticed that this individual had its proboscis coated with a large deposit of aggregated pollen.

Butterflies of the subfamily Heliconiinae are known as “passion vine butterflies” as many species use the genus Passiflora as a larval host plant. But they are also the only butterflies known to also feed on pollen, specifically from several species of the cucumber vine family, Cucurbitaceae. The passion vine butterflies have excellent eyesight and color vision allowing them to find the cucumber vine flowers in the forest. Nutrients in the pollen are essential for egg production and to maintain the health of the females‘ovaries which subsequently enable multiple matings. Daily feeding on pollen, from which amino acids are derived also allow the Heliconius butterflies to live anything upto 9 months which is almost Methuselah-like in butterfly terms. They are also metabolized into the production of defensive toxins stored in the butterflies’ body. The bright colors worn by the Heliconiinae are warnings, (aposomatic coloration), signaling that the insect is not a suitable food item.

Heliconius butterflies are trapliners, visiting several plants, but over the same route, every day. However if the food plants are in short supply, they become more stationary and defensive of their particular patch of vine.